define(function(require, exports, module) {
    // 2014.01.22  Support IE11 touch events.

    var $ = window.Zepto;

    // Zepto.js
    // (c) 2010-2014 Thomas Fuchs
    // Zepto.js may be freely distributed under the MIT license.

    var touch = {},
        touchTimeout,
        tapTimeout,
        swipeTimeout,
        longTapTimeout,
        longTapDelay = 750,
        gesture;

    function swipeDirection(x1, x2, y1, y2) {
        return Math.abs(x1 - x2) >=
            Math.abs(y1 - y2) ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
    }

    function longTap() {
        longTapTimeout = null;
        if (touch.last) {
            touch.el.trigger('longTap');
            touch = {}
        }
    }

    function cancelLongTap() {
        if (longTapTimeout) clearTimeout(longTapTimeout);
        longTapTimeout = null;
    }

    function cancelAll() {
        if (touchTimeout) clearTimeout(touchTimeout);
        if (tapTimeout) clearTimeout(tapTimeout);
        if (swipeTimeout) clearTimeout(swipeTimeout);
        if (longTapTimeout) clearTimeout(longTapTimeout);
        touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null;
        touch = {}
    }

    function isPrimaryTouch(event) {
        return (event.pointerType == 'touch' ||
            event.pointerType == event.MSPOINTER_TYPE_TOUCH)
            && event.isPrimary;
    }

    function isPointerEventType(e, type) {
        return (e.type == 'pointer' + type ||
            e.type.toLowerCase() == 'mspointer' + type);
    }

    $(document).ready(function() {
        var now, delta, deltaX = 0, deltaY = 0, firstTouch, _isPointerType;

        if ('MSGesture' in window) {
            gesture = new MSGesture();
            gesture.target = document.body;
        }

        $(document)
            .bind('MSGestureEnd', function(e) {
                var swipeDirectionFromVelocity =
                        e.velocityX > 1 ? 'Right' : e.velocityX < -1 ? 'Left' : e.velocityY > 1 ? 'Down' : e.velocityY < -1 ? 'Up' : null;
                if (swipeDirectionFromVelocity) {
                    touch.el.trigger('swipe');
                    touch.el.trigger('swipe' + swipeDirectionFromVelocity);
                }
            })
            .on('touchstart MSPointerDown pointerdown', function(e) {
                if ((_isPointerType = isPointerEventType(e, 'down')) && !isPrimaryTouch(e)) return;
                firstTouch = _isPointerType ? e : e.touches[0];
                if (e.touches && e.touches.length === 1 && touch.x2) {
                    // Clear out touch movement data if we have it sticking around
                    // This can occur if touchcancel doesn't fire due to preventDefault, etc.
                    touch.x2 = undefined;
                    touch.y2 = undefined;
                }
                now = Date.now();
                delta = now - (touch.last || now);
                touch.el = $('tagName' in firstTouch.target ?
                    firstTouch.target : firstTouch.target.parentNode);
                touchTimeout && clearTimeout(touchTimeout);
                touch.x1 = firstTouch.pageX;
                touch.y1 = firstTouch.pageY;
                if (delta > 0 && delta <= 250) touch.isDoubleTap = true;
                touch.last = now;
                longTapTimeout = setTimeout(longTap, longTapDelay);
                // adds the current touch contact for IE gesture recognition
                if (gesture && _isPointerType) gesture.addPointer(e.pointerId);
            })
            .on('touchmove MSPointerMove pointermove', function(e) {
                if ((_isPointerType = isPointerEventType(e, 'move')) && !isPrimaryTouch(e)) return
                firstTouch = _isPointerType ? e : e.touches[0];
                cancelLongTap();
                touch.x2 = firstTouch.pageX;
                touch.y2 = firstTouch.pageY;

                deltaX += Math.abs(touch.x1 - touch.x2);
                deltaY += Math.abs(touch.y1 - touch.y2);
            })
            .on('touchend MSPointerUp pointerup', function(e) {
                if ((_isPointerType = isPointerEventType(e, 'up')) && !isPrimaryTouch(e)) return;
                cancelLongTap();

                // swipe
                if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
                    (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

                    swipeTimeout = setTimeout(function() {
                        touch.el.trigger('swipe');
                        touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
                        touch = {}
                    }, 0);

                // normal tap
                else if ('last' in touch)
                // don't fire tap when delta position changed by more than 30 pixels,
                // for instance when moving to a point and back to origin
                    if (deltaX < 30 && deltaY < 30) {
                        // delay by one tick so we can cancel the 'tap' event if 'scroll' fires
                        // ('tap' fires before 'scroll')
                        tapTimeout = setTimeout(function() {

                            // trigger universal 'tap' with the option to cancelTouch()
                            // (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
                            var event = $.Event('tap');
                            event.cancelTouch = cancelAll;
                            touch.el.trigger(event);

                            // trigger double tap immediately
                            if (touch.isDoubleTap) {
                                if (touch.el) touch.el.trigger('doubleTap');
                                touch = {}
                            }

                            // trigger single tap after 250ms of inactivity
                            else {
                                touchTimeout = setTimeout(function() {
                                    touchTimeout = null;
                                    if (touch.el) touch.el.trigger('singleTap');
                                    touch = {}
                                }, 250)
                            }
                        }, 0)
                    } else {
                        touch = {}
                    }
                deltaX = deltaY = 0;
            })

            // when the browser window loses focus,
            // for example when a modal dialog is shown,
            // cancel all ongoing events
            .on('touchcancel MSPointerCancel pointercancel', cancelAll);

        // scrolling the window indicates intention of the user
        // to scroll, not tap or swipe, so cancel all ongoing events
        $(window).on('scroll', cancelAll);
    });

    ['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown',
        'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(eventName) {
            $.fn[eventName] = function(callback) {
                return this.on(eventName, callback)
            }
        });
});